Cell configuration method, synchronization method, user equipment, and base station

ABSTRACT

Embodiments of the present invention disclose a cell configuration method, a method for implementing synchronization between a user equipment and a base station, a user equipment, and a base station. The cell configuration method includes: determining, by a first base station corresponding to a first cell, system information of a second cell; and notifying, by the first base station, a second base station corresponding to the second cell of the system information, so that the second base station sends and receives signals according to the system information. According to the solutions provided in the embodiments of the present invention, system information of a cell may be dynamically or semi-statically adjusted according to user equipment distribution and service distribution, so that network resources can be better provided for a user equipment that needs them, a capability of serving the user equipment is improved.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation of International Patent ApplicationNo. PCT/CN2013/072804, filed on Mar. 18, 2013, which claims priority toChinese Patent Application No. 201210070828.5, filed on Mar. 16, 2012,both of which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to the field of communicationstechnologies, and in particular, to a cell configuration method, amethod for implementing synchronization between a user equipment and abase station, a user equipment, and a base station.

BACKGROUND

Most of existing wireless communication systems adopt cellular systems.In a cellular system, the whole system is divided into multiple cells,and the same time-frequency resources may be used in each cell or usedin multiple cells that are separated from each other at a certaindistance. When a whole network is divided into multiple cells, networkplanning needs to be performed. During the network planning, a positionof each base station in the network, the number of cells correspondingto a base station, a cell identity (ID) of each cell, and other systeminformation (including a carrier frequency, bandwidth, and the like)used by each cell need to be planned.

After the network planning is complete, each base station sends signalsaccording to the cell system information that has been planned. Whenaccessing the network, each user equipment needs to search for a celland access the cell. Then, the user equipment reads other relevantsystem information of the cell from a broadcast channel and thenestablishes a communication connection with a base station according tothe cell system information, such as a cell ID/carrier frequency of acarrier/system bandwidth/the number of antennas.

However, in a wireless communication system, after the network planningis complete, each cell ID and corresponding system information arefixed. Regardless of changes in user equipment distribution and servicerequirement distribution in a practical environment, only a cell systemplanned during the network planning can be used to provide a service fora user equipment, and cell system information in a network cannot beadjusted due to a change in user equipment distribution or servicerequirement distribution, so as to adjust a cell to adapt to the change.

For example, when one or more new cells are added to a network, networkreplanning needs to be performed for the whole network to allocate acell ID to the new cell. If the new cell is a temporary cell or the cellposition frequently changes, network replanning needs to be performedfor each change. As a result, complexity of network maintenanceincreases. However, if the new cell is allowed to randomly select a cellID by itself, it is likely to cause relatively large inter-cellinterference or a situation that is not applicable to servicedistribution in the network.

For another example, in a network including a macro cell and a microcell, if a main requirement of the network is to obtain more controlchannel capacities, the macro cell and the micro cell may be allowed touse different cell IDs. If the main requirement of the network is toobtain better inter-cell collaboration, the macro cell and the microcell may be allowed to use a same cell ID. When the main requirement inthe network changes, because a cell ID has been planned during thenetwork planning and cannot be changed, the existing network cannotaccommodate a change in the requirement.

In addition, when establishing a communication connection with a cell, auser equipment needs to establish initial downlink synchronization andsynchronization tracking with a base station and receives, based on thesynchronization, data sent by the base station, such as data of aphysical downlink shared channel (Physical Downlink Shared Channel,PDSCH). In an uplink, the base station needs to indicate a certaintiming advance (Timing Advance, TA) for the user equipment, and the userequipment determines an uplink transmission moment according toaccumulation of TAs received from the base station, a predefined offsetvalue, and the downlink synchronization.

In dynamic node selection (Dynamic Point Selection, DPS) transmissionmode, the user equipment needs to establish synchronization withmultiple nodes. However, the user equipment does not know referencesignals according to which synchronization is performed, synchronizationaccording to which a PDSCH is received, and synchronization according towhich the uplink transmission moment is determined.

SUMMARY

Embodiments of the present invention provide a cell configurationmethod, a method for implementing synchronization between a userequipment and a base station, a user equipment, and a base station.

In one aspect, an embodiment of the present invention provides a cellconfiguration method, including: determining, by a first base stationcorresponding to a first cell, system information of a second cell; andnotifying, by the first base station, a second base stationcorresponding to the second cell of the system information, so that thesecond base station sends and receives signals according to the systeminformation.

In another aspect, an embodiment of the present invention provides acell configuration method, including: receiving, by a user equipment ina first cell, system information of a second cell from a first basestation corresponding to the first cell; and communicating, by the userequipment, with a second base station corresponding to the second cellaccording to the system information.

In another aspect, an embodiment of the present invention provides abase station corresponding to a first cell, including: a determiningunit, configured to determine system information of a second cell; and asending unit, configured to notify a second base station correspondingto the second cell of the system information, so that the second basestation sends and receives signals according to the system information.

In another aspect, an embodiment of the present invention provides auser equipment, including: a receiving unit, configured to receivesystem information of a second cell from a first base stationcorresponding to a first cell; and a communication unit, configured tocommunicate with a second base station corresponding to the second cellaccording to the system information.

According to the solutions provided in the embodiments of the presentinvention, system information of a cell may be dynamically orsemi-statically adjusted according to user equipment distribution andservice distribution, so that network resources can be better providedfor a user equipment that needs them, a capability of serving the userequipment is improved, a requirement on network planning is lowered, itis simpler to establish a wireless communication network, and anadjustment capability of a network is enhanced.

In another aspect, an embodiment of the present invention provides amethod for implementing synchronization between a user equipment and abase station, including: determining configuration information of atleast one reference signal RS resource group or port group; and sendingthe configuration information to a user equipment, so that the userequipment establishes synchronization according to the configurationinformation of the at least one RS resource group or port group.

In another aspect, an embodiment of the present invention provides amethod for implementing synchronization between a user equipment and abase station, including: receiving configuration information of at leastone reference signal RS resource group or port group; and separatelyestablishing synchronization based on each RS resource group or portgroup and according to the configuration information.

In another aspect, an embodiment of the present invention provides abase station, including: a determining unit, configured to determineconfiguration information of at least one reference signal RS resourcegroup or port group; and a sending unit, configured to send theconfiguration information to a user equipment, so that the userequipment establishes synchronization according to the configurationinformation of the at least one RS resource group or port group.

In another aspect, an embodiment of the present invention provides auser equipment, including: a receiving unit, configured to receiveconfiguration information of at least one reference signal RS resourcegroup or port group; and a synchronizing unit, configured to separatelyestablish synchronization based on each RS resource group or port groupand according to the configuration information.

According to the solutions provided in the embodiments of the presentinvention, synchronization between a user equipment and a base stationis implemented, and the user equipment is capable of correctly receivingdata on a PDSCH channel and correctly determining uplink subframesending timing.

BRIEF DESCRIPTION OF DRAWINGS

To illustrate the technical solutions in the embodiments of the presentinvention more clearly, the following briefly introduces theaccompanying drawings required for describing the embodiments.Apparently, the accompanying drawings in the following description showmerely some embodiments of the present invention, and a person ofordinary skill in the art may still derive other drawings from theseaccompanying drawings without creative efforts.

FIG. 1 shows a flowchart of a cell configuration method that is proposedaccording to an embodiment of the present invention;

FIG. 2 shows a flowchart of a cell configuration method according toanother embodiment of the present invention;

FIG. 3 shows a schematic flowchart of communication performed between asecond base station and a user equipment in this embodiment after theyreceive system information sent by a first base station separately;

FIG. 4 shows a flowchart of a synchronization method according to anembodiment of the present invention;

FIG. 5 shows a flowchart of a synchronization method according toanother embodiment of the present invention;

FIG. 6 shows a flowchart of a synchronization method according toanother embodiment of the present invention;

FIG. 7 shows a flowchart of a synchronization method according toanother embodiment of the present invention;

FIG. 8 shows and further proposes a flowchart of a synchronizationmethod according to another embodiment of the present invention;

FIG. 9 shows a schematic structural diagram of a base station accordingto an embodiment of the present invention;

FIG. 10 shows a schematic structural diagram of a user equipmentaccording to an embodiment of the present invention;

FIG. 11 shows a schematic structural diagram of a base station accordingto an embodiment of the present invention; and

FIG. 12 shows a schematic structural diagram of a base station accordingto an embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

The following clearly describes the technical solutions in theembodiments of the present invention with reference to the accompanyingdrawings in the embodiments of the present invention. Apparently, thedescribed embodiments are merely a part rather than all of theembodiments of the present invention. All other embodiments obtained bya person of ordinary skill in the art based on the embodiments in thepresent invention without creative efforts shall fall within theprotection scope of the present invention.

FIG. 1 shows a flowchart of a cell configuration method that is proposedaccording to an embodiment of the present invention. As can be seen, themethod includes:

Step 110: A first base station corresponding to a first cell determinessystem information of a second cell.

In an implementation manner of this embodiment of the present invention,the system information of the second cell includes one or more of a cellidentity (Cell Identity, Cell ID), a carrier frequency of a carrier,bandwidth of a carrier system, a cyclic prefix (cyclic prefix, CP)length, the number of antennas, configuration information of a physicalhybrid automatic repeat request indicator channel (Physical hybrid-ARQindicator channel, PHICH), reference signal (Reference Signal, RS)sending power, a ratio of time division duplexing (Time DivisionDuplexing, TDD) subframes, configuration of an almost blank subframe(Almost Blank Subframe, ABS), maximum transmit power/power adjustment,subframe silence, and subband silence of the second cell. The cellidentity may be a physical cell identity. The system information may beinitialized system information of the second cell or updated systeminformation. For example, the initialized system information is systeminformation used to configure the second cell for the first time. Theupdated system information is system information reconfigured after thesystem information of the second cell is configured for the first time.That is, the system information of the second cell is set before, andthe updated system information refers to system information used toupdate the system information. Determining the system information may bedetermining one or more items of the system information, such asdetermining the cell ID only or determining both the cell ID and thecarrier frequency of a carrier. Optionally, the system information mayfurther include activation state information of the second cell. Theactivation state information is used to indicate one or more of thefollowing: whether the system information of the second cell isactivated, when it is activated, and an activation duration.

In the implementation manner of this embodiment, the first base stationmay determine all system information of the second cell, or partial orall system information of the second cell may be planned during networkplanning and the first base station determines the partial or all systeminformation of the second cell. When the partial system information ofthe second cell determined by the first base station is different fromcorresponding system information in the network planning, a second basestation corresponding to the second cell uses the system informationdetermined by the first base station.

The first cell may include the second cell in cell coverage, that is,the second cell may be a sub-cell in coverage of the first cell; it isalso possible that the first cell and the second cell do not overlap;and it is also possible that the first cell and the second cell overlappartially. For example, when the first cell includes the second cell inthe cell coverage, the first base station corresponding to the firstcell may determine the system information of the second cell accordingto user distribution information or service distribution information ina coverage area of the second cell measured by the first cell, and acell ID, a carrier frequency, and the like that have been used at thenetwork side. Alternatively, in a situation in which the first basestation corresponding to the first cell does not know the userdistribution information or the service distribution information in thecoverage area of the second cell, the first base station correspondingto the first cell may determine the system information of the secondcell by using the user distribution information or the servicedistribution information of the second cell measured at the network side(for example, a base station controller, a core network device, oranother network side device) and according to the cell ID, the carrierfrequency, and the like that have been used at the network side. In thisembodiment, preferably, when determining the system information of thesecond cell, the first base station may consider interference generatedin a network in a situation in which the second cell uses the systeminformation; that is, the first base station may select appropriatesystem information, so that when the second cell uses the systeminformation, minimum interference is generated in the whole network orpartial network or the generated interference is lower than a presetthreshold. When the system information includes a cell ID, according toa network requirement, the cell ID may be the same as or different froma cell ID of a neighboring cell, and the determined cell ID of thesecond cell may be the same as or different from a cell ID of the firstcell. When the system information is other system information, such assystem bandwidth, the determined system information of the second cellmay be the same as or different from system information corresponding tothe first cell, and it may also be determined that the systeminformation used by the second cell and the system information of thefirst cell are orthogonal, such as being orthogonal between used systembandwidth.

It should be further noted that step 110 may be triggered to beperformed when a preset condition is met. For example,

when one or more of the following conditions 1-3 are met, the first basestation corresponding to the first cell determines the cell ID of thesecond cell:

Condition 1: Interference generated due to a scrambling code betweenmultiple cells corresponding to the first base station is higher than afirst preset threshold.

Condition 2: The second cell is a cell that is newly added to thenetwork and for which initialization configuration has not beenperformed.

Condition 3: A control channel capacity requirement in coverage of thefirst base station exceeds a control channel capacity that can beprovided currently.

A low-interference cell ID set associated with each cell ID that hasbeen used in the network may be prestored in the first base station oracquired from another network device, and interference is lower than thefirst preset threshold when each optional cell ID in thelow-interference cell ID set and the cell ID associated with the set areused simultaneously. When condition 1 or condition 2 is met and step 110is triggered, the first base station first determines a low-interferencecell ID set associated with a cell ID of a neighboring cell around thesecond cell and then selects a cell ID from an intersection or a unionof multiple low-interference cell ID sets as the cell ID of the secondcell.

When condition 3 is met and step 110 is triggered, the first basestation may select a cell ID that is different from that of aneighboring cell of the second cell as the cell ID of the second cell.

When the following condition 4 or condition 5 is met, the first basestation corresponding to the first cell determines the carrier frequencyof the carrier and/or system bandwidth of the second cell.

Condition 4: Interference of the second cell to one or more neighboringcells is higher than a second preset threshold.

Condition 5: Service density in coverage of the second cell is less thana second preset threshold.

When condition 4 or condition 5 is met, the first base station may use atraversal manner to find at least one carrier frequency of a carrierfrom available carrier frequencies of carriers of the second cell, sothat an interference level between the second cell and a surroundingcell is lower than the second preset threshold after the second celluses the carrier frequency of the carrier and/or system bandwidth. Forexample, a carrier of the second cell may be adjusted from a firstcarrier to a second carrier, or the system bandwidth is adjusted from 10MHz to 5 MHz; or a carrier frequency is also adjusted when the systembandwidth is adjusted from 10 MHz to first 5 MHz.

When the following condition 6 or 7 is met, the first base stationcorresponding to the first cell determines the number of antennas of thesecond cell.

Condition 6: A fault occurs on some antennas of a base stationcorresponding to the second cell.

Condition 7: The number of CSI-RS resources in an area in which thesecond cell is located is insufficient.

When condition 6 or 7 is met, the first base station changes, forexample, a 4-antenna service of the second cell to a 2-antenna service,that is, determines that the number of antennas is 2.

When the following condition 8 is met, the first base stationcorresponding to the first cell determines RS power and/or maximumtransmit power of the second cell.

Condition 8: An interference level between the second cell and one ormore neighboring cells exceeds a preset third threshold.

When condition 8 is met, the first base station increases or decreasesthe RS power and/or maximum transmit power of the second cell until arequirement of the third threshold is met.

When the following condition 9 is met, the first base stationcorresponding to the first cell determines a ratio of uplink anddownlink subframes of the second cell.

Condition 9: In an uplink or downlink subframe, the interference levelbetween the second cell and one or more neighboring cells exceeds apreset fourth threshold.

When condition 9 is met, one or more uplink subframes of the second cellare changed to downlink subframes, and/or one or more downlink subframesof the second cell are changed to uplink subframes until a requirementof the fourth threshold is met.

When the following condition 10 is met, the first base stationcorresponding to the first cell determines a silent subframe of thesecond cell.

Condition 10: In some subframes, the interference level between thesecond cell and one or more neighboring cells exceeds a preset fifththreshold.

When condition 10 is met, the first base station makes one or moresubframes of the second cell silent until a requirement of the fifththreshold is met.

When the following condition 11 is met, the first base stationcorresponding to the first cell determines a silent subband of thesecond cell.

Condition 11: In some subbands, the interference level between thesecond cell and one or more neighboring cells exceeds a preset sixththreshold.

When condition 11 is met, the first base station makes one or moresubbands of the second cell silent until a requirement of the sixththreshold is met.

It should be noted that the first to sixth thresholds may be the same ordifferent; trigger conditions may further include conditions opposite tocondition 1 to condition 11, so that the first base station may performadjustment or settings opposite to the preceding examples.

Step 120: The first base station notifies the second base stationcorresponding to the second cell of the system information, so that thesecond base station sends and receives signals according to the systeminformation.

Here, the first base station may notify the system information throughany inter-site or inter-cell interface, such as an X2 interface or aprivate interface. After receiving the system information, the secondbase station may determine relevant parameters of the second cellaccording to the system information and send and receive signalsaccording to the relevant parameters. For example, according to thesystem information, downlink signals of the second cell are generated,and/or uplink signals from the second cell are received.

When the system information includes a physical cell ID, the relevantparameters include a scrambling code sequence, a position of an RS,synchronization signals, a position of a physical control formatindicator channel (Physical control format indicator channel, PCFICH),or another parameter relevant to the physical cell ID. Specifically,configuring the relevant parameters of the second cell according to thesystem information includes one or more of the following steps a-d:

Step a: Determine a scrambling code sequence according to a receivedphysical cell ID, so that the second base station corresponding to thesecond cell uses the scrambling code to perform scrambling and/ordescrambling.

Step b: Determine a position of an RS according to the received physicalcell ID. Specifically, a parameter v_(shift) of an RS such as a CRS(Cell-spcific Reference Signals, cell-specific reference signals) and/ora user equipment-specific (UE-specific) RS, may be determined, andtherefore a position of an RE thereof is determined. For example, whenthe physical cell ID is updated from 10 to 11, because v_(shift)=Cell IDmod 6, the v_(shift) is updated from 4 to 5, and therefore an effect ofadjusting inter-cell interference intensity and an interferenceprobability may be achieved.

Step c: Determine synchronization signals according to the receivedphysical cell ID. Specifically, the received physical cell ID may beused to generate a primary synchronization signal sequence and/or asecondary synchronization signal sequence.

Step d: Determine a position of a PCFICH according to the receivedphysical cell ID. The position of the PCFICH may be a position of an REin the entire bandwidth, where the RE corresponds to the PCFICH. Whenthe physical cell ID changes, because the RE position of the PCFICHchanges, the effect of adjusting the inter-cell interference intensityand the interference probability may be achieved.

When the system information includes a CP length, the relevantparameters include the CP length.

Step e: Determine, according to received information about the CPlength, whether to use a CP with an ordinary CP length or a CP with anextended CP length.

When the system information includes the system bandwidth, the relevantparameters include a subband size.

Step f: Determine the subband size according to received systembandwidth; for example, the system bandwidth is changed from 5 MHz to 10MHz, and therefore the corresponding subband size is updated from 6 RBsto 8 RBs.

When the system information includes the number of antennas, therelevant parameters include a code book size.

Step g: Determine, according to the received number of antennas, aselected code book and a transmission manner.

In an implementation manner of this embodiment, the first base stationmay predefine effective time of the system information of the secondcell or notify the second base station of the effective time of thesystem information. After receiving the system information of the secondcell, the second base station begins to use the corresponding systeminformation of the second cell according to the effective time. Theeffective time may be an absolute time. For example, the effective timemay be used to indicate that the system information takes effectimmediately after being received, or the activation state informationmay include an activation frame number or an activation subframe numberthat is used to indicate activation on the frame or subframe. Certainly,the effective time may also be a relative time. For example, systeminformation takes effect on a first subframe after the second basestation receives 100 radio frames of the corresponding systeminformation, or it may be indicated that the system information takeseffect after a given time (for example, 500 ms) after the systeminformation is received.

According to the preceding embodiment, a person skilled in the art mayknow that the first base station corresponding to the first cell iscapable of managing the second cell by determining the systeminformation of the second cell and sending it to the second base stationcorresponding to the second cell. The first base station may activatethe second cell and notify a user equipment of the activation of thesecond cell and the system information of the second cell, the firstbase station may also disable the second cell and simultaneously notifythe user equipment of relevant system information of the disabling ofthe second cell, and the first base station may also notify the userequipment of relevant system information for switching back to the firstcell or switching to another cell, such as a third cell, and so on. Aperson skilled in the art may think of these under the instruction ofthis embodiment of the present invention, and therefore details are notprovided herein.

In this embodiment of the present invention, the term “cell” includes aphysical cell or a carrier. A physical cell refers to a cellcorresponding to a physical device, and a cell corresponding to acarrier refers to that at least one set of physical devices work on atleast one carrier and each set of working physical devices on eachcarrier may correspond to one cell.

After the step 120, the first base station may further send the systeminformation or system information including the effective time to a userequipment in the first cell, so that the user equipment updates storedsystem information of the second cell or determines a relevant parameteraccording to the system information, and uses the updated systeminformation or the relevant parameter to access the second cell oradjusts a connection link with the second cell, for example, adjusts arelevant parameter used by the connection link, and receives signals ofthe second cell or sends signals to the second cell according torelevant system information, thereby implementing communication betweenthe user equipment and the second base station. It is also possible thatthe first base station sends the system information to the second cellor the third cell, and the second cell or the third cell sends thesystem information to the user equipment in the first cell, so that theuser equipment is capable of communicating with the second base stationcorresponding to the second cell according to the system information.This aspect is further described in the following embodiments.

It may also be that the first base station notifies the second cell oranother cell except the first and second cells of the system informationof the second cell and the effective time of the system information, andthen the second cell or the another cell except the first and secondcells notifies a user equipment of the system information or the systeminformation including the effective time. In this embodiment of thepresent invention, the first cell and the second cell may correspond toa same base station or different base stations. When the first cell andthe second cell correspond to the same base station, that is, when thefirst base station and the second base station are the same basestation, the second cell may be notified of the system informationthrough an internal interface of the base station or any otherinterface, including a private interface. When the first cell and thesecond cell correspond to different base stations, the first basestation may notify the second base station corresponding to the secondcell of the system information through an interface between the basestations, an X2 interface, or any other interface, including a privateinterface.

In this embodiment of the present invention, the first base station mayfurther determine system information of multiple cells simultaneouslyand notify a base station corresponding to each cell of the multiplecells of the determined system information, so that the base stationcorresponding to each cell generates downlink signals of thecorresponding cell and/or receives uplink signals from the correspondingcell according to the system information. In this case, the first basestation may determine that the system information of the multiple cellsis the same, such as determining that IDs of the multiple cell are thesame, or that the system information of the multiple cells is different,such as determining that IDs of the multiple cell are different, or thatsystem bandwidth of the multiple cells is the same but correspondingfrequency bands are orthogonal.

In this embodiment, system information of a second cell is determined bya first base station. Therefore, system information of a cell may bedynamically or semi-statically adjusted according to user distributionand service distribution requirements, so that network resources can bebetter provided for a user that needs them, a capability of serving theuser is improved, a requirement on network planning is lowered, it issimpler to establish a wireless communication network, and an adjustmentcapability of a network is enhanced.

FIG. 2 shows a flowchart of a cell configuration method according toanother embodiment of the present invention. Steps in this embodimentmay be performed on the basis of the embodiment corresponding to FIG. 1.The method in this embodiment includes:

Step 210: A user equipment in a first cell receives system informationof a second cell from a first base station corresponding to the firstcell.

The system information may be initialized system information or updatedsystem information. The system information further includes activationstate information, where the activation state information is used toindicate one or more of the following: whether the second cell isactivated, when it is activated, and an activation duration. The systeminformation may further be system information specific to the userequipment. All descriptions about a cell and system information in theembodiment corresponding to FIG. 1 are applicable to this embodiment,and therefore no further details are provided herein. In thisembodiment, the system information may be notified to the user equipmentthrough a broadcast message or be notified to the user equipment throughsignaling specific to the user equipment, for example, high levelsignaling such as RRC signaling.

Step 220: The user equipment communicates with a second base stationcorresponding to the second cell according to the system information.

After the user equipment receives the system information of the secondcell sent by the first base station corresponding to the first cell, theuser equipment may determine, according to the system information,relevant parameters that need to be used to communicate with the secondcell, where the relevant parameters are the same as those in thepreceding embodiment. For example, when the system information includesa physical cell ID, the relevant parameters include a scrambling codesequence, a position of an RS, synchronization signals, a position of aPCFICH, or another parameter relevant to the physical cell ID. A mannerof determining the relevant parameters is also the same as that in thepreceding embodiment. The second base station has adjusted the relevantparameters according to the system information in advance and sends andreceives signals according to the system information, so that both thesecond base station and the user equipment have adjusted the relevantparameters according to the system information. Therefore, the userequipment may receive signals of the second cell or send signalsaccording to relevant system information, so that communication can beperformed between the user equipment and the second base station.

According to an implementation manner, the method further includesreceiving time for updating the system information of the second celland updating the corresponding system information of the second cellaccording to the time for updating the system information.

FIG. 3 shows a schematic flowchart of communication performed between asecond base station and a user equipment in this embodiment after theyreceive system information sent by a first base station separately.First, the first base station in a first cell sends system informationof a second cell to the second base station and the user equipmentrespectively. Here, the system information may take effect in the secondbase station and the user equipment simultaneously, or the systeminformation may take effect in the second base station first and thentake effect in the user equipment, and so on. This does not affect theessence of the present invention. After both the second base station andthe user equipment determine relevant parameters according to the systeminformation, a connection link may be established or a connection linkmay updated between the second base station and the user equipment.

As can be seen from this embodiment of the present invention, systeminformation of a second cell is determined by a first base station.Therefore, system information of a cell may be dynamically orsemi-statically adjusted according to a user distribution requirementand a service distribution requirement, so that network resources can bebetter provided for a user that needs them, a capability of serving theuser is improved, a requirement on network planning is lowered, it issimpler to establish a wireless communication network, and an adjustmentcapability of a network is enhanced.

According to another embodiment of the present invention, a method forimplementing synchronization between a user equipment and a base stationis further proposed. It should be noted that before performing asynchronization method that is described in combination with FIG. 4 andFIG. 5, as a part of the present invention, the user equipment mayestablish initial synchronization according to primary synchronizationsignals (primary synchronization signal, PSS)/secondary synchronizationsignals (secondary synchronization signal, SSS) that are predefined orconfigured by a base station and then establish synchronizationaccording to multiple corresponding CSI-RS resources and the initialsynchronization. There is a mapping between the PSSs/SSSs and themultiple CSI-RS resources.

FIG. 4 shows a flowchart of a synchronization method according to anembodiment of the present invention. As can be seen, the method includesthe following steps:

Step 410: Determine configuration information of at least one referencesignal (Reference Signal, RS) resource group or port group. RSs mayinclude channel-state information-reference signals (Channel-StateInformation-Reference Signal, CSI-RS) and cell-specific referencesignals (Cell-specific Reference Signals, CRS). The resource group mayinclude one or more resources, and the port group may include one ormore ports.

Step 420: Send the configuration information to a user equipment, sothat the user equipment establishes synchronization according to theconfiguration information of the at least one RS resource group or portgroup.

In this embodiment, configuration of an RS resource group or port groupincludes a pilot pattern, bandwidth, a frequency domain position, acycle, a subframe offset, and the like of each RS resource or port inthe corresponding RS resource group or port group. An implementationmanner is notifying the user equipment of configuration parameters ofeach RS resource or port in all RS resource groups or port groups usedfor the synchronization, where the configuration parameters may includeparameters such as the pilot pattern, the bandwidth, the frequencydomain position, the cycle, and the subframe offset. An implementationmanner is instructing the user equipment to establish thesynchronization for each RS resource or port in all existing RS resourcegroups or port groups according to currently notified parameters. Animplementation manner may be notifying the user equipment of an RSresource group or port group used for the synchronization andsimultaneously notifying each RS resource group or port group of certainconfiguration information used for the synchronization. In this case,the user equipment overwrites existing corresponding configurationinformation of corresponding RS resources or ports with the notifiedconfiguration information so as to obtain RS resources or ports used forthe synchronization and establishes the synchronization according tothese RS resources or ports. For example, No. 0, 1, and 2 CSI-RSresources that have been notified to the user equipment are used toestablish the synchronization, where each CSI-RS resource serves as aresource group; when corresponding configuration information aboutbandwidth is that bandwidth of a CSI-RS resource group used for thesynchronization is six resource blocks (Resource Block, RB) and acorresponding frequency domain position is at the center of a frequencyband, the user equipment separately performs the synchronization onlyaccording to the three CSI-RS resources each with six RBs at the centerof the frequency band. Another implementation manner may be notifyingthe user equipment that three CSI-RS resources groups used for thesynchronization include No. 0, 1, and 2 CSI-RS resources each and acorresponding cycle is 5 ms. However, when corresponding configurationinformation used for the synchronization is that a cycle is 20 ms, theuser equipment only uses the cycle of 20 ms to separately perform thesynchronization on the corresponding three CSI-RS resources. When an RSport is used for the synchronization, the RS port is a set of one ormore ports of an RS resource; for example, the first port or the firsttwo ports of a 4-port CSI-RS resource may be used to perform thesynchronization.

In another implementation manner, RS configuration used for thesynchronization may also reuse RS configuration in a measurement set (aset of corresponding RSs used to measure channel state information) or afeedback set (a set of corresponding RSs used to determine feedbackinformation). That is, the measurement set or the feedback set is an RSset used for the synchronization, and the measurement set or thefeedback set may already include the RS configuration. In step 410,configuration information of an RS resource group or port group on whichthe synchronization needs to be performed may be determined by directlyusing such configuration in the measurement set or the feedback set.After receiving configuration information of the measurement set or thefeedback set, the user equipment separately establishes thesynchronization based on the CSI-RS and CRS resource or portconfiguration. For example, the measurement set includes No. 0, 1, and 2CSI-RS resources, each CSI-RS resource corresponds to four ports, entirebandwidth, a cycle with a length of 20 ms, and a subframe offset equalto 5, where the No. 0, 1, and 2 CSI-RS resources correspond to pilotpatterns 0, 1, and 2, respectively, and the user equipment directly usesthe corresponding three CSI-RS resources to establish thesynchronization separately. Based on the measurement set or the feedbackset, it may further be notified that some CSI-RS resources or CSI-RSports in the set are CSI-RS resource groups or CSI-RS port groups onwhich the synchronization needs to be performed, where each resourcegroup includes one resource and each port group includes at least oneport (the number of ports in each port group may be predefined, forexample, one port or the first two ports corresponding to a resource).Further, some or all CSI-RS resources or CSI-RS ports in the measurementset or the feedback set may further be notified of the configurationinformation used for the synchronization. In this case, the userequipment performs the synchronization on a certain RS resource or portby using corresponding configuration information used for thesynchronization that is currently notified, instead of correspondingconfiguration information corresponding to an existing RS resource orport. It is assumed that the measurement set is used for thesynchronization simultaneously, where the measurement set includes No.0, 1, and 2 CSI-RS resources, each CSI-RS resource corresponds to fourports, entire bandwidth, a cycle with a length of 20 ms, and a subframeoffset equal to 5, and the No. 0, 1, and 2 CSI-RS resources correspondto pilot patterns 0, 1, and 2, respectively, but a cycle with a lengthof 40 ms is used for the synchronization. In this case, the userequipment uses No. 0, 1, and 2 CSI-RS resources whose cycle length is 40ms to establish the synchronization separately.

Here, the user equipment may establish one or more synchronization.Moreover, establishment of the synchronization may also be implementedby the user equipment according to a certain trigger condition. Forexample, the trigger condition may be that some measurement or feedbackneeds to be performed according to a synchronized CSI-RS/CRS resource orport, and presynchronization is required in this case; or the triggercondition may be that reference signal received power or referencesignal received quality corresponding to a CSI-RS/CRS resource or portthat needs to be synchronized exceeds a certain threshold; certainly,the trigger condition may also be another thinkable trigger condition.In this embodiment of the present invention, synchronization may bereplaced with synchronization tracking, timing, and the like, and thepreceding method is still applicable.

In this embodiment, sending configuration information to a userequipment may allow the user equipment to establish synchronizationaccording to configuration information of each resource group or portgroup, thereby solving a problem that the user equipment does not knowreference signals based on which synchronization is to be performed.

According to an embodiment, after the establishing synchronizationbetween a user equipment and a base station, the following steps mayfurther be performed to implement receiving PDSCH data by the userequipment. FIG. 5 shows a flowchart of a synchronization methodaccording to an embodiment of the present invention.

As can be seen from FIG. 5, step 410 and step 420 are completely thesame as the steps shown in FIG. 4, and therefore details are notrepeated herein.

Step 430: Determine first synchronization information to which referenceneeds to be made by the user equipment for receiving a physical downlinkshared channel PDSCH. Here, the base station may determine the firstsynchronization information by itself, or the base station may obtainthe first synchronization information in another manner. Here,determining the first synchronization information may be performed inthe following manner: first determining a transmitting node that is usedto transmit the physical downlink shared channel, and then determiningsynchronization corresponding to signals of an RS resource group or anRS port group transmitted by the transmitting node as the firstsynchronization information.

Step 440: Send the first synchronization information to the userequipment, so that the user equipment determines, according to the firstsynchronization information, synchronization that needs to be used, toreceive data from the PDSCH. In step 410, the user equipment mayestablish multiple synchronization with the base station. Therefore, thebase station determines synchronization according to which the userequipment needs to receive data from the PDSCH, that is, determines thefirst synchronization information. In step 440, the base station maysend the first synchronization information to the user equipment inmultiple manners. For example, in dynamic node selection (Dynamic PointSelection, DPS) mode, the first synchronization information may betransmitted through a downlink control information (Downlink ControlInformation, DCI) notification; in single-node service mode, the firstsynchronization information may be transmitted through radio resourcecontrol (Radio Resource Control, RRC) signaling or a DCI notification;in joint transmission (Joint Transmission, JT) mode, the firstsynchronization information may be transmitted through RRC signaling ora DCI notification, for example, the user equipment may be instructed touse a CSI-RS corresponding to the nearest node to performsynchronization. It should be noted that the preceding examples are notexhaustive, and a person skilled in the art is likely to think of thatanother suitable manner may be used to send the first synchronizationinformation to the user equipment. Through the first synchronizationinformation, the user equipment is capable of learning thesynchronization according to which it needs to receive the PDSCH data.The first synchronization information may be notified according to anumber of an RS resource group or port group that is used for thesynchronization. For example, the RS resource group or port group thatis used for the synchronization is numbered according to a sequence forthe base station to notify RS resources used for the synchronization,and when the first synchronization information is notified, only acorresponding number of a corresponding RS resource group or port groupis notified. A bitmap (bitmap) manner may also be used for notifying; inthis case, each bit in a bitmap corresponds to an RS resource group orport group used for the synchronization, a bit corresponding to firstsynchronization is set to 1, and another bit is set to 0, so that thebitmap can be used to effectively notify the first synchronizationinformation.

According to the preceding solution, the user equipment may select,according to an instruction of the base station, requiredsynchronization to receive the PDSCH data, thereby correctly receivingthe data on the PDSCH.

According to an embodiment, after the establishing synchronizationbetween a user equipment and a base station that is described incombination with FIG. 4, the following steps may further be performed toimplement determining, by the user equipment, a transmission moment forsending uplink information. FIG. 6 shows a flowchart of asynchronization method according to an embodiment of the presentinvention. In the method shown in FIG. 6, how to determine an uplinktransmission moment according to downlink synchronization is described.As can be seen from FIG. 6, step 410 and step 420 are completely thesame as the steps shown in FIG. 4, and therefore details are notrepeated herein.

Step 450: Determine second synchronization information to whichreference needs to be made by the user equipment when sending uplinksignals. Here, the base station may determine the second synchronizationinformation by itself, or the base station may obtain the secondsynchronization information by using another manner.

Step 460: Send the second synchronization information to the userequipment, so that the user equipment is capable of determining,according to the second synchronization information, a transmissionmoment for sending the uplink signals.

The user equipment has established multiple synchronization with thebase station. Therefore, in step 450, the base station determines thesecond synchronization information to which reference needs to be madeby the user equipment in an uplink direction. For example, the basestation determines that second synchronization of the user equipment issynchronization that has been established by a certain user equipment (adetermining method may be using same synchronization as the secondsynchronization all the time, or determining synchronizationcorresponding to a node that receives uplink information of the userequipment as the second synchronization), and the user equipment needsto determine, according to timing of the synchronization, a referencevalue for adjusting the uplink transmission moment. For example, whenthe user equipment learns that the second synchronization is thesynchronization that has been established by the certain user equipment,it may determine, according to the synchronization and an uplink TA, anuplink transmission moment for sending uplink information. Moreover, theuser equipment may determine a timing offset before and after the secondsynchronization changes, and determine, according to the timing offset,the second synchronization, and a parameter such as the uplink TA, anuplink transmission moment for sending uplink data. For example,according to a notification of the base station, the secondsynchronization changes from synchronization A to synchronization B, anda synchronization timing offset between synchronization A and B isΔoffset; in this case, the user equipment needs to adjust the TA toTA′=TA+Δoffset and then use the corresponding TA′ and the secondsynchronization notified by the base station to determine the uplinktransmission moment. A method for notifying the second synchronizationinformation may be the same as a method for notifying the firstsynchronization information, for example, notifying a number ofcorresponding synchronization or using a bitmap to notify the secondsynchronization that needs to be used.

As an implementation manner, it may further include notifying the userequipment of whether timing offset compensation needs to be performed,and the user equipment determines, according to the notification,whether timing offset compensation needs or does not need to beperformed. When compensation needs to be performed, the user equipmentfirst determines a timing compensation offset, then adjusts a TA to aTA′ according to the timing offset compensation, and then determines anuplink transmission moment according to the TA′ and the secondsynchronization notified by the base station.

Certainly, it is also possible that the user equipment is predefined toperform timing compensation according to a certain trigger condition.For example, the user equipment determines whether a change of thesecond synchronization exceeds a predetermined threshold, and when thechange of the second synchronization exceeds the preset threshold, theuser equipment adjusts a TA according to a changed timing offset of thesecond synchronization, for example, automatically adjusts the value ofthe TA to TA′=TA+Δoffset, where the Δoffset is a timing offset beforeand after the second synchronization changes. When both a triggercondition and a notification of the base station exist, the userequipment performs, only when the trigger condition is met and the basestation notifies that the timing offset compensation needs to beperformed, timing offset compensation and determines an uplinktransmission moment according to the compensated TA′.

Therefore, the user equipment may send uplink signals according to theuplink transmission moment determined by the second synchronization.

The methods shown in FIG. 5 and FIG. 6 may be performed separately orjointly. Accordingly, FIG. 7 shows a flowchart of a synchronizationmethod according to another embodiment of the present invention. As canbe seen, the method includes:

Step 710: Determine configuration information of at least one referencesignal (Reference Signal, RS) resource group or port group. RSs mayinclude CSI-RSs and CRSs.

Step 720: Send the configuration information to a user equipment, sothat the user equipment establishes synchronization with a base stationbased on each resource group or port group and according to theconfiguration information.

Step 730: Determine first synchronization information to which referenceneeds to be made by the user equipment for receiving a physical downlinkshared channel PDSCH.

Step 740: Send the first synchronization information to the userequipment, so that the user equipment determines, according to the firstsynchronization information, synchronization that needs to be used, toreceive data from the PDSCH channel.

Step 750: Determine second synchronization information to whichreference needs to be made by the user equipment when sending uplinkdata.

Step 760: Send the second synchronization information to the userequipment, so that the user equipment is capable of determining,according to the second synchronization information, a transmissionmoment for sending uplink signals.

It should be noted that the above description does not limit a sequenceof performing the steps. For example, steps 750 and 760 may be performedfirst, and then steps 730 and 740 are performed. This does not changethe essence of this embodiment of the present invention and falls in thescope disclosed in this embodiment of the present invention.

As can be seen, uplink synchronization and downlink synchronization ofthe user equipment are determined by using the preceding method, so thatcommunication in uplink and downlink directions can be performed betweenthe user equipment and the base station. For specific content of thesteps of the preceding method, reference may be made to the foregoingdescription in combination with FIG. 4 to FIG. 6, and details are notrepeated herein.

Accordingly, according to an embodiment of the present invention, amethod for implementing synchronization between a user equipment and abase station is further proposed. FIG. 8 shows a flowchart of themethod. As can be seen, the method includes: Step 810: Receiveconfiguration information of at least one reference signal RS resourcegroup or port group on which synchronization needs to be performed; andstep 820: Separately establish synchronization with a base station basedon each RS resource group or port group and according to theconfiguration information.

According to an implementation form, the method further includes:receiving first synchronization information corresponding to a PDSCH;and determining, according to the first synchronization information,synchronization that needs to be used, to receive data from the PDSCHchannel.

According to an implementation form, the method further includes:receiving second synchronization information to which reference needs tobe made when uplink signals are sent; and determining, according to thesecond synchronization information, a transmission moment for sendingthe uplink signals.

According to an implementation form, the method further includes:receiving signaling about whether offset compensation needs to beperformed for timing; and compensating changed second synchronizationaccording to a timing offset before and after the second synchronizationchanges.

According to an implementation form, the method further includes:determining whether a change of the second synchronization exceeds apredetermined threshold; and when the predetermined threshold isexceeded, adjusting timing of the second synchronization according to achanged timing offset of the second synchronization.

According to an implementation form, the method further includes:establishing initial synchronization according to primarysynchronization signals and/or secondary synchronization signalsPSSs/SSSs that are predefined or configured by the base station.

For specific content of the preceding method, reference may be made tothe foregoing embodiments described from the base station side incombination with FIG. 4 to FIG. 7, and therefore no further details areprovided herein.

According to an embodiment of the present invention, a base station isfurther proposed, and it corresponds to a first cell. FIG. 9 shows aschematic structural diagram of a base station according to anembodiment of the present invention. As can be seen, the base station900 includes: a determining unit 910, configured to determine systeminformation of a second cell; and a sending unit 920, configured tonotify a second base station corresponding to the second cell of thesystem information, so that the second base station sends and receivessignals according to the system information.

According to an implementation form, the determining unit 910 isspecifically configured to: dynamically or semi-statically update thesystem information of the second cell; or trigger the first base stationto determine the system information of the second cell when a presetcondition is met.

According to an implementation form, the sending unit 920 is configuredto send the system information to a user equipment in the first cell, sothat the user equipment is capable of communicating with the second basestation corresponding to the second cell according to the systeminformation; or the sending unit 920 is configured to send the systeminformation to the second cell or a third cell, where the second cell orthe third cell sends the system information to a user equipment in thefirst cell, so that the user equipment is capable of communicating withthe second base station corresponding to the second cell according tothe system information.

According to an implementation form, the sending unit 920 furthernotifies a user equipment of time when the system information of thesecond cell takes effect, so that the user equipment updates thecorresponding system information of the second cell according to thetime when the system information takes effect.

According to an embodiment of the present invention, a user equipment isfurther proposed. FIG. 10 shows a schematic structural diagram of a userequipment according to an embodiment of the present invention. The userequipment 1000 includes: a receiving unit 1010, configured to receivesystem information of a second cell from a first base stationcorresponding to a first cell; and a communication unit 1020, configuredto communicate with a second base station corresponding to the secondcell according to the system information. It should be noted that thecommunication unit 1020 may also include the communication unit 1010,and the accompanying drawing does not limit them as independent units.

According to an implementation form, the user equipment further includesan updating unit 1030. The receiving unit 1010 receives time when thesystem information of the second cell takes effect, and the updatingunit 1030 is configured to update the corresponding system informationof the second cell according to the time when the system informationtakes effect.

According to an embodiment of the present invention, a base station isfurther proposed. FIG. 11 shows a schematic structural diagram of a basestation according to an embodiment of the present invention. The basestation 1100 includes: a determining unit 1110, configured to determineconfiguration information of at least one reference signal RS resourcegroup or port group; and a sending unit 1120, configured to send theconfiguration information to a user equipment, so that the userequipment establishes synchronization according to the configurationinformation of the at least one RS resource group or port group.

According to an implementation form, the determining unit 1110 isconfigured to determine first synchronization information to whichreference needs to be made by the user equipment for receiving aphysical downlink shared channel PDSCH; and the sending unit 1120 isconfigured to send the first synchronization information to the userequipment, so that the user equipment determines, according to the firstsynchronization information, synchronization that needs to be used, toreceive data from the PDSCH.

According to an implementation form, the determining unit 1110 isconfigured to determine second synchronization information to whichreference needs to be made by the user equipment when sending uplinksignals; and the sending unit 1120 is configured to send the secondsynchronization information to the user equipment, so that the userequipment is capable of determining, according to the secondsynchronization information, a transmission moment for sending theuplink signals.

According to an implementation form, the base station further includes:a notifying unit 1130, configured to notify the user equipment ofwhether offset compensation needs to be performed for an uplink timingadvance, so that the user equipment is capable of determining an uplinktransmission moment according to a timing offset before and after thesecond synchronization changes.

According to an implementation form, the notifying unit 1130 isconfigured to notify the user equipment of primary synchronizationsignals and/or secondary synchronization signals PSSs/SSSs, so that theuser equipment establishes initial synchronization according to theprimary synchronization signals and/or secondary synchronizationsignals.

According to an embodiment of the present invention, a user equipment isfurther proposed. FIG. 12 shows a schematic structural diagram of a basestation according to an embodiment of the present invention. As can beseen, the user equipment 1200 includes: a receiving unit 1210,configured to receive configuration information of at least onereference signal RS resource group or port group; and a synchronizingunit 1220, configured to separately establish synchronization based oneach RS resource group or port group and according to the configurationinformation.

According to an implementation form, the user equipment further includesa determining unit 1230. The receiving unit 1210 is configured toreceive first synchronization information corresponding to a PDSCH, andthe determining unit 1230 is configured to determine, according to thefirst synchronization information, synchronization that needs to beused, to receive data from the PDSCH.

According to an implementation form, the receiving unit 1210 isconfigured to receive second synchronization information to whichreference needs to be made when uplink signals are sent; and thedetermining unit 1230 is configured to determine, according to thesecond synchronization information, a transmission moment for sendingsignals.

According to an implementation form, the receiving unit 1210 isconfigured to receive second synchronization information to whichreference needs to be made when uplink signals are sent; and thedetermining unit 1230 is configured to determine, according to thesecond synchronization information, a transmission moment for sendingsignals.

According to an implementation form, the receiving unit 1210 isconfigured to receive signaling about whether offset compensation needsto be performed for an uplink timing advance; and the determining unit1230 is configured to determine an uplink transmission moment accordingto a timing offset before and after the second synchronization changes.

According to an implementation form, the user equipment further includesan adjusting unit 1240. The determining unit 1230 is configured todetermine whether a change of the second synchronization exceeds apredetermined threshold; and the adjusting unit 1240 is configured to:when the predetermined threshold is exceeded, adjust timing of thesecond synchronization according to a changed timing offset of thesecond synchronization.

According to an implementation form, the synchronizing unit 1220 isfurther configured to establish initial synchronization according toprimary synchronization signals and/or secondary synchronization signalsPSSs/SSSs that are predefined or configured by a base station.

For specific details about the preceding apparatus embodiments,reference may be made to relevant parts of the foregoing methodembodiments, and therefore no further details are provided herein.

A person skilled in the art should understand that the division of theapparatuses and modules in the embodiments of the present invention islogical function division and their practical specific structures may bea split or combination of the foregoing functional modules.

Serial numbers of the above embodiments of the present invention areonly used for description, but do not indicate preference of theembodiments.

Solutions described in claims also fall within the protection scope ofthe embodiments of the present invention.

A person of ordinary skill in the art may understand that all or a partof the processing of the methods in the embodiments may be implementedby a program instructing relevant hardware. The program may be stored ina computer readable storage medium.

The foregoing describes only exemplary embodiments of the presentinvention and is not intended to limit the protection scope of thepresent invention. Any modification, equivalent replacement, orimprovement made without departing from the spirit and principle of thepresent invention shall fall within the protection scope of the presentinvention.

1. A method for implementing synchronization between a user equipmentand a base station, comprising: determining configuration information ofat least one reference signal (RS) resource group or port group; andsending the configuration information to a user equipment to facilitatesynchronization between the user equipment and the base stationaccording to the configuration information of the at least one RSresource group or port group.
 2. The method according to claim 1,further comprising: determining first synchronization information towhich the user equipment needs to make reference for receiving aphysical downlink shared channel (PDSCH); and sending the firstsynchronization information to the user equipment, so that the userequipment determines, according to the first synchronizationinformation, synchronization within the established synchronizationrequired to receive data from the PDSCH.
 3. The method according toclaim 2, wherein the sending the first synchronization information tothe user equipment comprises: sending downlink control information (DCI)including the first synchronization information corresponding to thePDSCH.
 4. The method according to claim 1, wherein the synchronizationcomprises one or more of synchronization tracking or timing.
 5. A methodfor implementing synchronization between a user equipment and a basestation, comprising: receiving configuration information of at least onereference signal (RS) resource group or port group; and separatelyestablishing synchronization for each RS resource group or port groupaccording to the configuration information of the RS resource group orport group.
 6. The method according to claim 5, further comprising:receiving first synchronization information corresponding to a PDSCH;and determining, according to the first synchronization information,synchronization within the established synchronization required toreceive data from the PDSCH.
 7. The method according to claim 6, whereinthe receiving first synchronization information corresponding to a PDSCHcomprises: receiving downlink control information (DCI) including thefirst synchronization information corresponding to the PDSCH.
 8. Themethod according to claim 5, wherein, the synchronization comprises oneor more of synchronization tracking or timing.
 9. A base station,comprising: a determining unit, configured to determine configurationinformation of at least one reference signal (RS) resource group or portgroup; and a sending unit, configured to send the configurationinformation to a user equipment to facilitate synchronization betweenthe user equipment and the base station according to the configurationinformation of the at least one RS resource group or port group.
 10. Thebase station according to claim 9, wherein: the determining unit isconfigured to determine first synchronization information to which theuser equipment needs to make reference for receiving a physical downlinkshared channel (PDSCH); and the sending unit is configured to send thefirst synchronization information to the user equipment, so that theuser equipment determines, according to the first synchronizationinformation, synchronization within the established synchronizationrequired to receive data from the PDSCH.
 11. The base station accordingto claim 10, wherein sending the first synchronization information tothe user equipment comprises: sending downlink control information (DCI)including the first synchronization information corresponding to PDSCH.12. The method according to claim 9, wherein, the synchronizationcomprises one or more of synchronization tracking or timing.
 13. A userequipment, comprising: a receiving unit, configured to receiveconfiguration information of at least one reference signal (RS) resourcegroup or port group; and a synchronizing unit, configured to separatelyestablish synchronization for each RS resource group or port groupaccording to the configuration information of the RS resource group orport group.
 14. The user equipment according to claim 13, the userequipment further comprising a determining unit, wherein: the receivingunit is configured to receive first synchronization informationcorresponding to a PDSCH; and the determining unit is configured todetermine, according to the first synchronization information,synchronization within the established synchronization required toreceive data from the PDSCH.
 15. The method according to claim 14,wherein receiving first synchronization information corresponding to aPDSCH comprises: receiving downlink control information (DCI) includingthe first synchronization information corresponding to the PDSCH. 16.The method according to claim 13, wherein, the synchronization comprisesone or more of synchronization tracking or timing.